The present invention relates to the field of security entrance systems and more particularly relates to a security entrance system for restricting access from one area to another area.
Many security systems depend on perimeter protection against contraband. For example, in a typical airport security system, devices such as electromagnetic metal detectors are used to prevent smuggling of weapons from an unprotected area, also referred to as the xe2x80x9cinfeedxe2x80x9d areaxe2x80x9d into the protected area of the airport terminal. Metal detectors and other devices adapted to detect weapons can be deployed in a similar manner to protect other protected areas as, for example, military installations, utility control centers, police stations and other installations susceptible to terrorism. A similar perimeter protection approach can be applied using devices to detect other types of contraband. For example, drug detection devices rather than metal detectors can be applied at customs entry ports. In this instance, the infeed area may constitute the region accessible to incoming travelers prior to customs inspection, whereas the protected area may constitute the free or unrestricted, post-customs region.
Protection using only a detection device such as a metal detector requires constant monitoring of the boundary between the infeed area and the protected area. If the monitoring personnel relax their vigilance even a moment, a smuggler can enter or pass contraband through the opening protected by the detector. For this reason, automatic doors can be used in combination with contraband detectors such as metal detectors. For example, a metal detector may be connected to an automatic door at the entry to the protected area, so that the metal detector detects any metal carried by the person before the person reaches the door and opens the door only if no metal is detected. If the metal detector has detected metal, the door does not open and the person must pass back into the in-feed area through the metal detector. Such a system can be defeated by a smuggler who simply leaves contraband such as a gun behind at the door, just past the metal detector, in a region which is not examined by the metal detector system. The smuggler steps back out of the system through the metal detector. He then surrenders some innocent metal object such as keys to the security officers monitoring the system to provide an innocent explanation for the initial metal detection and re-enters the protected area through the metal detector, which does not detect any metal. As the door opens, the smuggler retrieves the contraband and enters the protected area.
Some security systems restrict access to a protected area to a designated set of individuals. For example, an entrance to an industrial plant may be provided with doors which require a physical token such as a unique pass card or entry of a unique code to open the door. Other systems use biometric measurements such as hand measurements, pupillary pattern recognition or other biometric parameters to identify a particular authorized user. For example, an employee may insert his or her hand into the machine and physical measurements of the hand may be checked against a database of hand measurements for authorized users. Such arrangements may be combined with a contraband detection system as discussed above. To obtain entry, the employee presents his or her pass card, enters his or her code or provides a biometric measurement. If the system recognizes the pass card, code or biometric measurement, it allows the employee to open the door and also records the identity of the employee and the time of entry. Such systems theoretically can exclude unauthorized persons and can also keep track of the entries and exits of authorized persons. However, these systems can be defeated if more than one person enters the protected area when the door is open. For example, if a first authorized person enters the proper code, the door will operate in response to the code. Two or more people may enter the protected area when the door operates. If an authorized person is careless, or if an authorized person is acting under duress, he or she may let an unauthorized person enter the protected area.
Accordingly, despite all of the effort which has been devoted to contraband detection and security entrance systems in the art heretofore, there are still considerable needs for improvement in security systems and methods.
The present invention addresses these needs.
One aspect of the present invention provides a security entrance system for restricting access from an infeed area to a protected area. A security system in accordance with this aspect of the invention desirably includes a structure defining an enclosed chamber with a first opening connecting the interior of the chamber with the infeed area and a second opening connecting the interior of the chamber with the protected area. The structure defining the chamber includes one or more first doors movable between a closed position in which the first doors block the first opening and an open position in which the first doors do not block such opening. The structure defining the chamber also includes one or more second doors movable between a closed position in which the second doors block the second opening and an open position in which the second doors do not block the second opening. This system desirably further includes a detector arranged to detect contraband entering the chamber through the first opening as, for example, a electromagnetic or other known metal detector for detecting weapons, a chemical detector such as an ion scan system or other chemically sensitive system for detecting chemical contraband such as drugs or explosives.
The system further includes a chamber monitoring system which is connected to the structure. The chamber monitoring system is arranged to detect at least one characteristic of the structure defining the chamber. Preferably, the chamber monitoring system is arranged to detect the weight of the structure. The entrance system according to this aspect of the invention desirably also includes a controller connected to the doors, the detection system and the chamber monitoring system.
The controller desirably is arranged to operate cyclically. In one normal operating mode, each cycle of the controller includes an entry phase in which the first door is open to allow a person entry to the chamber, and the detection system is actuated to monitor the entrance to the chamber for contraband. In a further phase of the cycle, the first door or doors are closed and the second door or doors are allowed to open only if no contraband was detected in the entry phase and only while the first door is closed. Thus, the system will not allow a person into the protected area through the second opening unless the first door is closed and no contraband was detected. If no contraband was detected, the cycle ends when the person passes through the second opening, whereupon the second door or doors close. If contraband was detected, the first door or doors are reopened and the cycle ends when the person passes back out of the chamber through the first opening.
At the end of each cycle, or at least at the end of each cycle in which contraband passing into the chamber was detected by the metal detector or other contraband detector, the controller checks the structure characteristic such as the weight of the structure and chamber when no person is present in the chamber. The controller is arranged to inhibit operation of at least one of the doors during the next cycle if the characteristic of the structure determined by the monitoring system differs from a normal value of such characteristic. For example, if the weight of the chamber-defining structure with no person in the chamber is heavier than its normal empty weight, after the end of a cycle in which the metal detector issued an alarm, the controller may inhibit opening of the first door or the second door. Stated another way, after contraband has been detected in the chamber when a person leaves, the system shuts down and blocks access to the protected area until the condition is cleared manually by security personnel.
Thus, the system will inhibit passage of a person through the system into the protected area if an object is left in the chamber by a preceding person. Likewise, if a smuggler leaves a gun or other contraband within the chamber and steps back out of the chamber, the monitoring system will prevent the smuggler from entering the protected area by re-entering the chamber. The security personnel monitoring the system can reset the system to resume normal operation after inspecting the chamber.
Desirably, the structure is arranged to enclose the interior of the chamber so that a person who is disposed within the chamber with both doors closed cannot reach any part of the system which is not a part of the structure monitored by the chamber monitoring system. Stated another way, the system is arranged so that when the doors are closed, every surface which the person inside the chamber can touch is part of the structure which is weighed or otherwise measured by the monitoring system. Therefore, it is impossible for a person to conceal contraband within the chamber.
However, after a cycle has started, the controller is arranged to permit open the first door if opening of the second door is inhibited. Therefore, if a person is denied access to the protected area by inhibition of the second door opening, as if contraband is detected, the person can pass back into the infeed area from the chamber through the first opening. The person will not be trapped within the chamber. Typically, the security entrance system is arranged to emit an alarm signal if contraband is detected or if the chamber monitoring system detects a change in the characteristics of the chamber as, for example, a change in the weight of the chamber. Typically, the chamber monitoring system includes a base and one or more force transducers connected between the chamber and the base for providing signals related to the weight of the chamber, doors and associated structures. The system optionally may include an activation system for testing a person seeking entry and providing an authorization signal to the controller if such test is passed, thereby establishing that the person is an authorized user. The controller can be arranged to inhibit operation of at least one of the doors if no authorization signal is received from the activation system. For example, the activation system may include a keypad for manual entry of codes and a code comparator for comparing the entered codes to valid codes; a token detector for detecting a badge or other token issued to authorized users; or biometric measurement devices for measuring a biometric characteristic of a person seeking entry.
The same weighing system used to weigh the structure defining the chamber-defining structure when no person is present may also be used to weigh the structure during a cycle while a person is present in the chamber. The controller may be arranged to inhibit operation of the second door unless the detected weight is within preset parameters. For example, the system may be arranged to inhibit operation of the second door if the total weight of the chamber and associated structures with a person in the chamber is above a predetermined maximum threshold, thus indicating that two or more persons are present in the chamber. A fixed maximum threshold may be applied for all authorized users as, for example, about 100 kg over the normal, empty weight of the chamber and associated structures. This provides protection against entry of an unauthorized person along with an authorized person.
Alternatively or additionally, the system may be arranged to inhibit operation of the second door if the weight of the chamber and structures is below a preset person-present threshold as, for example, 6 ounces to 10 Kg above the empty weight of the structure, indicating that no one is present in the chamber.
Where the activation system detects the identity of the user as, for example, by entry of individualized user codes or the use of individualized tokens or biometrics, the system may be arranged to allow opening of the second door only if the total weight of the system is within a relatively narrow range of weights corresponding to the weight with the particular identified individual plus the normal empty weight of the chamber. Weighing systems of this nature assure that the second door will not be opened if the authorized user is accompanied by another person or if a different person has somehow obtained the authorized user""s code or token.
The foregoing embodiments of the system provide significant safeguards against entry of unauthorized persons along with authorized persons. Moreover, the weight threshold testing features can be provided using the same weighing system which is used to weigh the chamber and structures while no person is present. Stated another way, the additional security afforded by weight checking while a person is present, and the additional security provided by weighing the empty chamber and associated structures can be accomplished using the same structural elements.
Still further aspects of the present invention provide methods of restricting access to a protected area. Methods according to this aspect of the invention desirably include the steps of providing a chamber having one or more first doors and one or more second doors, opening the first doors to allow a person entry into the chamber from a infeed area and sensing for contraband as the person enters the chamber. Methods according to this aspect of the invention further include the step of closing the first door and opening the second door if no contraband was sensed as the person entered the chamber so as to allow the person in the chamber access to the protected area. The method includes the step of maintaining the second door closed if contraband was sensed. Most preferably, the method according to this aspect of the invention includes the additional step of detecting the presence of objects remaining in the chamber after a person has vacated the chamber, and inhibiting further opening of at least one of the doors if an object is detected in the chamber. As discussed above with reference to the apparatus, methods according to this aspect of the invention can use a weighing system or other system for measuring the weight or other physical characteristics defining the chamber. Also as discussed above with reference to the apparatus, the methods desirably include weighing the chamber while a person is present therein and comparing the detected weight to a threshold or range. Such threshold or range which may be a generic for all persons or may be a specific threshold or range for a specific authorized user of the system.
These and other objects, features and advantages of the present invention will be more readily apparent from the detailed descriptions set forth below, taken in conjunction with the accompanying drawings.